This invention relates to delivering fluid to a multitude of fluid utilizing devices and more particularly to a valve which is capable of maintaining a predetermined flow rate therethrough while routing incoming fluid flow to selected utilizing devices, receiving fluid streams returning therefrom, and recombining the returning fluid streams into an outgoing fluid flow.
It is necessary to provide cool lubricating oil to the bearings in a turbine so as to improve the oil's lubricating characteristics and prevent it from reaching its flash point. Normally, steam turbines which are utilized in large central station applications have a dual oil cooler arrangement in which either cooler has sufficient capacity to cool the lubricating oil. While the turbine is operating, only one cooler is normally in use with the second cooler remaining inactive and providing backup capability for the first cooler. If maintenance or repair is required for the first, primary cooler, the second cooler must be brought on line without interrupting lubricating oil flow to the turbine. Interruption of the oil flow to the turbine can cause serious turbine damage and result in expensive turbine-generator forced outages. Valves previously utilized to accomplish the simultaneous primary cooler shutdown and secondary cooler startup were of the three-way type and were expensive, difficult to handle due to their high weight and responsible for high pressure drops in the oil lubrication system.